This invention relates to an operational testing device for exhaust systems, and more particularly to an apparatus for testing an exhaust system of an internal combustion engine. The test setup has multiple heater inputs, as well as a system for controlling the thermal and fluid loading throughout an engine block.
Devices for testing the thermal integrity of exhaust systems under varying thermal loading are known in the automotive industry. Often, these systems use a standard internal combustion engine dynamometer coupled to the exhaust system to provide heat and fluid flow. While dynamometers provide realistic vibration and heat flows through the engine exhaust system, these systems are often complicated to set up as well as expensive to run over long periods of time.
A second simpler static system utilizes a standard engine block disposed on a frame for providing heat to the exhaust system. These static systems use a single gas input to a set of burners for providing heat and gas flow into the cylinders of an automotive engine block. They typically have a single valve for regulating the gas into a plurality of burners disposed within the cylinders of an engine. Unfortunately, as gas flow through these cylinders often is different, the heating of individual cylinders frequently varies, leading to the thermo-gradients throughout the engine block. This can lead to improper test simulations and premature failure of the tested components and test hardware. It has also been found that the static simulators may not properly simulate fluid flow through the exhaust system.
It is an object of the present invention to provide a testing device for the exhaust system for an internal combustion engine, is simple, yet improved. The system offers many of the advantages of controlling the amount of heat and fluid flow into a particular cylinder of a test engine.
In general, the test device has an engine block that defines a number of cylinders having an access port through the bottom of the engine block. Coupled to each cylinder access port is an input plenum having a burner assembly disposed therein. The burner assembly is operatively coupled to a gas or fluid fuel source which effects the amount of gas and, hence, the temperature of a given engine cylinder. A valve set is disposed between the fluid source and a burner assembly for regulating the amount of gas to each individual burner. A controller is provided for adjusting the amount of fuel through the valve set based upon signals provided by a set of thermal couples distributed throughout the engine block. Coupled above the cylinders of the engine block is an altered engine head. The altered engine head provides a mechanism by which the exhaust system to be tested is coupled to the test stand.
In an alternate embodiment of the present invention, a system for pulsating the fluid flow through the engine block cylinders into the exhaust system is provided. A plurality of paddles are disposed within the combustion gas stream to regulate the amount of fluid flow from the engine block to the exhaust system.
Generally, the exhaust system to be tested has an exhaust manifold that is coupled to the exhaust ports of the engine block""s head. Typically connected to the exhaust manifold is tubing, a catalytic converter and a muffler. The testing is conducted on the exhaust system to ensure that the systems meet the durability requirements of the automotive original equipment manufacturers.